The MFC-8640D uses TN-540 black toner, with TN-570 as the high-yield choice. DR-520 is the separate drum and should not be confused with either toner cartridge.
The genuine Brother selection at Toner Buzz covers TN-540, TN-570, and the DR-520 drum. Choose TN-540 or TN-570 when toner is needed, and select DR-520 only when the printer identifies a drum issue.
Guaranteed fit for Brother MFC-8640 D
The products below are genuine OEM Brother Supplies made for the Brother MFC-8640 D.